For FY11, we have used multi-dimensional NMR and site-directed mutagenesis methods to assign the chemical shifts of methyl groups of Val, Leu, and Ile of histones in the nucleosome. They were used as probes for studying the dynamics of nucleosome and its interactions with other proteins such as linker histone H1 and high mobility group nucleosomal proteins (HMGN). We have determined the structure of the HMGN2-nucleosome complex. We have also investigated the structure of Scm3 complexed with centromere histone variant Cse4 and histone H4. Our studies are important for understanding how DNAs are separated during cell division and provide insights on how mis-separation of DNAs may cause human diseases.